Red Hat Bugzilla – Bug 144060
[PATCH] speedstep-centrino support for dothan pentium-m
Last modified: 2015-01-04 17:14:41 EST
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Description of problem:
The kernels distributed with FC3 (up to the 220.127.116.115 version in
updates/testing) seem to be missing support for intel's Dothan Pentium-M.
The processors are recognized, but the speedstep-centrino module only
has support for acpi frequency scaling on them.
This compared to the older Banias model's 'table' support, which means
that cpufreq knows more than max/min speeds, and is able to scale
fluently between them
Here's a patch wich adds support for all Dothan cpu's up to the 755
version (2.0 Ghz).
Applying this patch to the latest FC3 kernels seem to work for me
(dothan 1.6ghz, stepping b0), and it also patches into the official
Version-Release number of selected component (if applicable):
Steps to Reproduce:
boot and check frequencies on dothan pentium-m's
Created attachment 109317 [details]
speedstep-centrino dothan frequency table patch
Is anything likely to happen with this patch? I note that it was posted to the
LKML, but no there was no response there.
It would be really helpfull if speedstepping for the Pentium-M was available
without a kernel rebuild.
We can't do table support on Dothans -- there are four different voltage
settings -- and using VID#C (like the patch does) is not necessarily the one
needed for one platform. And VID#C is higher than VID#D so it even might
cause hardware damage.